Prior art self-standing, collapsible ladders have not been entirely satisfactory, requiring compromises in desired size, height and stability in use for satisfactory bulk, weight and size in handling and storage. Further, prior self-standing, collapsible ladders have been difficult to erect and collapse, without unduly compromising safety.
Applicants are aware of the below listed prior art patents:
______________________________________ U.S. PAT. NO. PATENTEE ______________________________________ 826,582 Laird 1,051,950 Francis 1,206,628 Webster 1,973,774 Pflugradt 3,311,190 Naumann 4,030,565 Chaput ______________________________________
______________________________________ SWISS PATENT NO. PATENTEE ______________________________________ 430,985 Spoerle ______________________________________